Septic Tanks

1 April 2022 – 3 Minute Read

How does a septic tank work, and is it airtight?

A septic tank is a large underground container made from glass, reinforced plastic or high density polyethylene that partially treats and stores sewerage and waste water. Septic tanks are most common in properties that are not connected to a mains sewerage system. A septic tank uses gravity to separate solid and liquid waste that comes into it from a connected property. Lighter waste floats to the surface while heavier soiling sinks to the bottom. Waste is then broken down by anaerobic bacteria. The liquids in between the sludge layer at the top and bottom flow out of the tank and into the surrounding soil area, which is known as a septic soakaway. A septic tank needs to be watertight and airtight.

How much is it to empty a septic tank?

Expect to pay around £200 for a septic tank company to empty and professionally clean your septic tank. The fee should typically involve drainage, cleaning, waste removal, chemical cleaning and repairs. The costs could be more than this if you have a larger tank, if your tank has multiple chambers and if it is not easy to access.

How do I know when to empty a septic tank – and how often should I empty it?

You will typically need to empty an average household septic tank once a year, regardless of whether it is full or not. This advice is given by the UK Environment Agency. You may need to empty your tank two or three times a year, depending on size and how often toilets are flushed at your property. It is very important to have your septic tank serviced and de-sludged by a reputable septic tank company as this will ensure that the septic tank works correctly. You can find a septic tank specialist in your area using . You will know when to empty your septic tank because your toilets will start to flush more slowly and you may find dirty water accumulating in the drainage field. A septic tank engineer will let you know if you have a blockage when they come to empty it, and inform you of any repairs that need to be undertaken.

How much is a septic tank?

For general domestic septic tank systems, expect to pay in the region of £1,250 . The price you pay for a septic tank will always depend on its size. If you need a 2,800 litre tank that caters for up to 5 people, you should expect to pay around £550 . If you want a very large 79,000 litre water tank for a large building, this will cost about £12,000 .

Do I need to add bacteria to my septic tank?

If you have a septic tank, you do not need to add bacteria to it. Research has suggested that in the UK, the moderate climate causes a slower anaerobic rate of digestion to occur, causing septic tanks to function as sedimentation tanks. To add extra bacteria might upset this delicate biological process and the septic tank should already have all the microorganisms that it requires to break down the waste inside it.

What can you put over a septic tank?

It is important when planting around a septic tank that you do not choose invasive trees or plants that can block or damage your drains. Choose fibrous rooted shrubs, such as holly or boxwood, and place them between the drain runs if you are planting them in a soakaway field. Planting grass is usually a popular choice as this is low maintenance and non-invasive. Choose herbaceous plants rather than plants that love water, such as willow or hydrangeas.

Can septic tanks be above ground?

Yes, you can install a septic tank above ground. Having a tank above ground makes access much easier and makes it possible for you to join more than one tank together if you need a larger tank.

Are flushable wipes okay for septic tanks?

If you flush any kind of wipe that is not biodegradable toilet paper into your septic tank, you could clog and damage the septic tank system. This is because even branded flushable wipes do not break down once in the septic tank and it can affect the flow of water through the system.